Aquarium



FIG. 1 is a top view of an aquarium showing my new ornamental design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a right side elevational view thereof, the left side being a mirror image of the side shown; and,

FIG. 6 is a perspective view taken from the top front and right side thereof. 

The ornamental design for an aquarium, as shown and described. 